Projection type image display apparatus

ABSTRACT

A first exhaust fan  17  for mainly discharging exhaust air from a light source lamp  19  to exterior and a second exhaust fan  18  for mainly discharging exhaust air from parts other than the light source lamp  19  are arranged to be parallel to each other. An end of the exhaust fan  17  facing the other exhaust fan  18  is moved to the inner side and the one exhaust fan  17  is inclined to discharge air in an exhaust direction toward a direction along which air is discharged from the other exhaust fan  18 . There is provided a cooling fan  16  that blows air to an interior air blow outlet  161  communicating with the interior of the light source lamp  19  and exterior air blow outlets  162  and  163  communicating with an outer surface to cool the light source lamp  19 . The exterior air blow outlets  162  and  163  are deviated from the center of the outer surface of the light source lamp  19 . The cooling fan  16  is used to allow the exhaust air used for cooling the light source lamp  19  to be discharged through the first exhaust fan  17 . The first exhaust fan  17  is inclined so that exhaust air is sucked by the first exhaust fan  17  in a direction to the exterior air blow outlets  162  and  163 . As a result, a projection type image display apparatus can be minimized while achieving the cooling of the light source lamp, the reduction of the exhaust air temperature, and the reduction of noise of the exhaust fan.

FIELD OF THE INVENTION

The invention of the present application relates to a projection typeimage display apparatus that modulates light emitted from a light sourcelamp based on an image signal to project the modulated image light in anexpanded manner. In particular, the invention relates to a structure forcooling the light source lamp and a structure for exhausting heat in theapparatus.

BACKGROUND OF THE INVENTION

A projection type image display apparatus of a liquid crystal projectorfor example is required to achieve both of a higher output of a lightsource lamp and a minimization. Thus, a luminous tube in a reflector ofa light source lamp uses a high-pressure mercury lamp or a metal halidelamp for example that emits light with a high intensity at a hightemperature. However, a part of the light source lamp having the highesttemperature is heated to a temperature of about 1000° C. and thus thelight source lamp is cooled by air blown from a fan. This light sourcelamp exhausts air of a high temperature that is higher than that of apower source unit. Thus, the high temperature is solved by maximizingthe capability of the exhaust fan (rotating speed), by increasing thesize of the exhaust fan, or by providing a plurality of exhaust fans.

Japanese Patent Laid-Open Publication No. H09-90511 (PatentPublication 1) discloses a projection type image display apparatushaving a fan for cooling a light source lamp in which a part of a ductextending from this fan to a light source lamp that is opposed to thelight source lamp includes an opening (air blow outlet). Japanese PatentLaid-Open Publication No. 2000-19644 (Patent Publication 2) discloses aprojection type image display apparatus structured so that two exhaustfans are provided in parallel to each other in the vicinity of a lightsource lamp to discharge exhaust air from the light source lamp or apower source unit for example.

However, in the above conventional light source lamp cooling mechanismas disclosed in Patent Publication 1, the fan and the air blow outletare arranged in consideration of only the cooling of the light sourcelamp. Thus, when this structure cools the light source lamp, thisstructure causes a proportional increase in the temperature of theexhaust air. An excessively-high exhaust air temperature causes anincreased number of complaints from users. Furthermore, the structure ofPatent Publication 2 requires an increased interval between a side wallof a housing and the exhaust fans arranged to be parallel to each other,thus hindering the structure from being minimized. For reducing thetemperature of the exhaust air, a structure may be considered in whichexhaust air of a high temperature from the light source lamp and exhaustair of a low temperature from the power source unit for example can bemixed by inclining the respective exhaust fans arranged to be parallelto each other to form an inverted V-like shape in the exhaust directionsthereof. However, this structure also requires a space and thus ishindered from being minimized.

In the conventional technique as described above, the cooling of thelight source lamp having a high output causes an increased temperatureof an exhaust air, which exceeds a permissible range of users, thusmaking it difficult to achieve both of the cooling of the light sourcelamp and the reduction of the exhaust air temperature. When thedifficulty is tried to be solved by increasing the output of the fan orby increasing the number of fans, a disadvantage is caused in whichnoise is increased or the apparatus is prevented from being minimized.

SUMMARY OF THE INVENTION

The invention of the present application has been made in view of thepoint as described above. It is an objective of the invention to providea projection type image display apparatus that achieves the cooling ofthe light source lamp and the reduction of the exhaust air temperatureand that can be minimized while reducing the noise from the exhaust fan.

In order to achieve the above objective, the invention of the presentapplication is characterized in a projection type image displayapparatus that modulates light emitted from a light source lamp based onan image signal to project the modulated image light in an expandedmanner. The projection type image display apparatus is including a firstexhaust fan for mainly discharging exhaust air from the light sourcelamp to exterior, and a second exhaust fan for mainly dischargingexhaust air from parts other than the light source lamp to exterior thatare arranged to be parallel to each other. These fans are arranged sothat an end of one exhaust fan facing the other exhaust fan is moved tothe inner side and the one exhaust fan is inclined to discharge air inan exhaust direction toward a direction along which air is dischargedfrom the other exhaust fan.

According to this structure, an end of one exhaust fan facing the otherexhaust fan is moved to the inner side. This structure can form aninterval between a side wall of a housing and the one exhaust fanwithout hindering the structure from be minimized and can reduce noise.This structure also can mix the exhaust air of a high temperature fromthe light source lamp with the exhaust air of a relatively lowtemperature from parts other than the light source lamp, thus reducingthe temperature of the exhaust air.

In this case, a space can be obtained between the light source lamp andthe second fan. Thus, an end of the first exhaust fan facing the secondexhaust fan is preferably moved to the inner side, and the first exhaustfan is inclined to have the exhaust direction facing the exhaust side ofthe second exhaust fan.

The second exhaust fan is preferably structured to mainly dischargeexhaust air from the power source unit to exterior.

This structure also can simultaneously perform the discharge of exhaustair from an important power source unit that has a temperature not sohigh as the light source lamp.

The first exhaust fan is preferably inclined to an exhaust hole formedin the side wall of the housing.

This structure can allow exhaust air of a high temperature from thelight source lamp to be discharged through the exhaust hole in aninclined direction. Thus, the exhaust air is proportionally difficultlydischarged therethrough and thus can be easily mixed with the exhaustair of a relatively low temperature from the second exhaust fan. Thus,the exhaust air temperature can be further reduced.

The first exhaust fan is preferably inclined so that the exhaust air isdischarged through the exhaust hole formed in the side wall of thehousing to the front side in an inclined direction.

This structure can prevent the exhaust air having a high temperaturefrom being blown in a lateral direction leading to a user.

In the present invention, it is preferable that a cooling fan that blowsair to an interior air blow outlet communicating with the interior ofthe light source lamp and an exterior air blow outlet communicating withan outer surface to cool the light source lamp is provided. The exteriorair blow outlet is deviated from the center of the outer surface of thelight source lamp. The cooling fan is used to allow the exhaust air usedfor cooling the light source lamp to be discharged through the firstexhaust fan. The first exhaust fan is inclined so that air is sucked bythe first exhaust fan in a direction to the exterior air blow outlet.

According to the above structure, the interior of the light source lamphaving a luminous tube of the highest temperature can be efficientlycooled by the interior air blow outlet. The outer surface of the lightsource lamp having a temperature not so high as the interior of thelight source lamp can be appropriately cooled by the exterior air blowoutlet deviated from the center of the outer surface. Furthermore, thefirst exhaust fan is inclined so that air is sucked by the first exhaustfan in a direction to the exterior air blow outlet. Thus, air blownthrough the exterior air blow outlet deviated from the center of theouter surface of the light source lamp cools the outer surface of thelight source lamp and a part thereof is directly sucked by the firstexhaust fan and is mixed with exhaust air having the temperatureelevated by cooling the interior of the light source lamp, and isexhausted to exterior. Thus, the temperature of the exhaust air can bereduced. Thus, both of the cooling of the light source lamp and thereduction of the exhaust air temperature can be achieved withoutexcessively increasing the output of the fan and noise can be reduced.

In this case, the exterior air blow outlet is preferably deviated fromthe center of the outer surface of the light source lamp and is dividedinto two parts, consisting of upper and lower parts.

The above structure can cool the outer surface of the light source lampin a substantially uniform manner.

A degree at which the exterior air blow outlet is deviated from thecenter of the outer surface of the light source lamp and a degree atwhich the second fan is inclined so that air is sucked by the second fanin a direction to the exterior air blow outlet are preferably determinedin consideration of the cooling of the light source lamp and the exhaustair temperature.

The structure as described above can flexibly achieve both of thecooling of the light source lamp and the reduction of the exhaust airtemperature in accordance with the light source lamp having a higheroutput or the apparatus being minimized.

The interior air blow outlet and the exterior air blow outlet arepreferably formed in a duct extending from the first fan to the lightsource lamp.

The structure as described above can improve the freedom degree of thearrangement of the first fan.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a liquid crystal projector according toone embodiment of a projection type image display apparatus of thepresent invention, obliquely seen from above from the front side.

FIG. 2 is similarly a perspective view obliquely seen from above fromthe back side.

FIG. 3 is a perspective view in which an upper case in FIG. 1 isremoved.

FIG. 4 is a perspective view in which a main control substrate isfurther removed.

FIG. 5 is a perspective view in which an optical system is furtherremoved.

FIG. 6 is a top plan view of FIG. 5.

FIG. 7 is a view showing a configuration example of an optical system.

FIG. 8 is an enlarged view of principal parts showing a light sourcelamp cooling mechanism in the present embodiment, and is also aperspective view obliquely seen from above from the front side.

FIG. 9 is similarly a perspective view in which an upper half of a ductis removed and obliquely seen from above from the back side.

FIG. 10 is a perspective view in which a holder of the light source lampin FIG. 9 is removed.

FIG. 11 is a cross-sectional view of the principal parts seen from theback side.

FIG. 12 is an enlarged view of the principal parts showing an opticalpart cooling mechanism in the present embodiment, and is also aperspective view obliquely seen from above from the front side.

FIG. 13 is similarly a top plan view.

FIG. 14 is similarly a top plan view in which the optical parts areremoved.

FIG. 15 is similarly a back side view in which the lower half of theduct is removed.

FIG. 16 is a perspective view showing an exhaust fan unit constitutingan exhaust mechanism in the present invention.

FIG. 17 is similarly a perspective view showing the back side.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

One embodiment of the present invention will now be described below indetail with reference to the drawings.

FIG. 1 is a perspective view of a liquid crystal projector as oneembodiment of a projection type image display apparatus according to thepresent invention seen obliquely from above from the front side, FIG. 2is similarly a perspective view seen obliquely from above from the backside, FIG. 3 is a perspective view in which the upper case in FIG. 1 isremoved, FIG. 4 is a perspective view in which a main control substrateis further removed, FIG. 5 is a perspective view in which an opticalsystem is further removed, and FIG. 6 is a top plan view of FIG. 5.

As shown in FIGS. 1 and 2, a housing 2 forming an outer hull of thisliquid crystal projector 1 is compact, has a horizontally long thinrectangular shape, and consists of an upper case 2 a and a lower case 2b. When the upper case 2 a and a main control substrate 3 are removed,the interior thereof is displayed as shown in FIG. 4.

The left side seen from the front side of the front wall of the uppercase 2 a is formed with a projection window 5, from which a projectionlens 4 is exposed. The left side front portion of the upper surface ofthe upper case 2 a is formed with an operation window 6, from which anadjustable dial 4 a that adjusts zooming and focusing of the projectionlens 4 corresponding to the projection window 5 is exposed. The leftside back portion of the upper surface of the upper case 2 a is providedwith an operation display portion 7.

On the other hand, the right side wall of the lower case 2 b seen fromthe front side is formed with a plurality of slit-like exhaust holes 8.Both side corner portions of the bottom front portion of the lower case2 b are provided with leg portions 9 adjustable in height. On thebackside wall of the lower case 2 b, a power source inlet 10 connectedto a power source plug and an inlet and outlet terminal group 11 toconnect various types of input and output cables are exposed.

Inside the housing 2, as shown in FIGS. 3 and 4, looking from the frontside, the right side inner portion is disposed with a light source unit12, and at the same time, an optical system 13 reaching the projectionlens 4 from the light source unit 12 is disposed approximately inL-shape. In front of the light source unit 12, a power source main body14 stored with a power source circuit substrate mounted with the circuitparts to feed a power source to each portion of the apparatus and aballast circuit substrate mounted with circuit parts to feed the powersupply exclusively to the light source lamp is disposed, and in the backof the light source unit 12, a noise removal filter portion 15 to removethe noise infiltrating through the power source inlet 10 is disposed.

In the present embodiment, the noise removal filter portion 15 isseparated from the power source unit main body 14, and at the same time,the separated noise removal filter portion 15 is disposed to bepositioned as closely as possible to the housing back side wall providedwith the power source inlet 10 and the power source unit main body 14.Specifically, along the front side wall of the horizontally long house2, the power source unit main body 14 is disposed, and at the positionopposite to the power source unit main body 14 in the back side wall,the noise removal filter portion 15 mounted with a core (coil) 15 a andthe like on the substrate is disposed along the back side wall.

On the other hand, at the back side in an irradiating direction of thelight source unit 12, a suction fan 16 composed of a sirocco fan as afirst fan including the light source lamp cooling mechanism is disposed,and at the lateral side, an exhaust fan 17 composed of an axial fan as asecond fan constituting the light source lamp cooling mechanism isdisposed.

At the lateral side of the power source unit main body 14, an exhaustmechanism is provided. This exhaust mechanism is configured such that anexhaust fan 18 composed of the axial fan as a second exhaust fan ishorizontally disposed side by side with the exhaust fan 17.Incidentally, the exhaust fan 17 as the second fan constituting thelight source lamp cooling mechanism serves as the first exhaust fanconstituting the exhaust mechanism.

FIG. 7 is a view showing a configuration example of the optical system13. Incidentally, the optical system 13 is not limited to the one shownin FIG. 7 and the present invention can be applied to the apparatussprovided with various types of optical systems.

In FIG. 7, a white light from the light source lamp 19 passes through acondenser lens 20, a first integrator lens 21, a second integrator lens22, a polarizing beam splitter (PBS) 23, and a condenser lens 24 or thelike, and is irradiated at a first dichroic mirror 25.

The first integrator lens 21 and the second integrator lens 22 areconfigured by the fly-eye lenses composed of a plurality of lens cellsdisposed in a matrix array, and have functions to equalize theillumination distribution of the white light emitted from the lightsource lamp 19.

The polarizing beam splitter (PBS) 23 includes a polarizing separationmembrane and a phase retardation plate (½ wave plate). The polarizingseparation membrane allows, from among the light from the secondintegrator lens 22, for example, a P polarization to transmit, and an Spolarization slightly to change the light path and emit. The Ppolarization light having transmitted the polarization separationmembrane is converted into the S polarization by the phase retardationplate provided in the front side (light emitting side) thereof, and isemitted. That is, almost all the lights are aligned by the Spolarization.

The light having passed through the polarizing beam splitter 23 passesthrough a condenser lens 24, and reaches the first dichroic mirror 25.The first dichroic mirror 25 reflects a blue component only of thelight, and at the same time, has a function to allow red and greencomponents to pass through, and the passing light of the red and greencomponents reaches a second dichroic mirror 26. The second dichroicmirror 26 reflects a green component of the light, and at the same time,has a function to allow the red component to pass through. Consequently,the white light emitted from the light source lamp 19 is divided intothe blue light, the green light, and the red light by the first andsecond dichroic mirrors 25 and 26.

The blue light reflected by the first dichroic mirror 25 is reflected bya total reflection mirror 27, and the green light reflected by thesecond dichroic mirror 26 is as it is, and the red light having passedthe second dichroic mirror 26 is reflected by total reflection mirrors29 and 31 via relay lens 28 and 30, and these are guided to an imagegenerating optical system 32, respectively.

The image generation optical system 32 is detachably disposed with aprism assembly part 35 (see FIG. 4) fitted with a liquid crystal panel34 r for the red color, a liquid crystal panel 34 g for the green color,a liquid crystal panel 34 b for the blue color, and the like,respectively, at the three lateral sides of a cube-shaped colorsynthesis prism 33. Between the color synthesis prism 33 and the liquidcrystal panel 34 r for the red color, an outgoing side polarizing plate36 r is disposed, and between the color synthesis prism 33 and theliquid crystal panel 34 g for the green color, an outgoing sidepolarizing plate 36 g and a fronting polarizing plate 37 g are disposed,and between the color synthesis prism 33 and the liquid crystal panel 34b for the blue color, an outgoing side polarizing plate 36 b and afronting polarizing plate 37 b are disposed. At the incident sides ofthree pieces of the liquid crystal panels 34 r, 34 g, and 34 b, incidentside polarizing plates 38 r, 38 g, and 38 b, and condenser lenses 39 r,39 g, and 39 b are disposed, respectively.

Consequently, the blue light reflected by the first dichroic mirror 25and the total reflection mirror 27 is guided to the condenser lens 39 bfor the blue color, and reaches the color synthesis prism 33 by passingthrough the incident side polarizing plate 38 b, the liquid crystalpanel 34 b for the blue color and the fronting polarizing plate 37 b,and the outgoing side polarizing plate 36 b. The green light reflectedby the second dichroic mirror 26 is guided to the condenser lens 39 gfor green color, and reaches the color synthesis prism 33 by passingthrough the incident side polarizing plate 38 g, the liquid crystalpanel 34 g for the green color and the fronting polarizing plate 37 g,and the outgoing side polarizing plate 36 g. Likewise, the red colorlight transmitting the first dichroic mirror 25 and the second dichroicmirror 26, and reflected by two pieces of the total reflection mirrors29 and 31, is guided to the condenser lens 39 r for the red color, andreaches the color synthesis prism 33 by passing through the incidentside polarizing plate 38 r, the liquid crystal panel 34 r for the redcolor and the outgoing side polarizing plate 36 r.

Three colors of image light guided by the color synthesis prism 33 issynthesized by this color synthesis prism 33, and the color image lightobtained by this synthesis passes through the projection lens 4, therebyto be enlargedly projected onto a frontward screen.

FIGS. 8 to 11 are enlarged views of principal parts showing the lightsource lamp cooling mechanism in the present embodiment. FIG. 8 is aperspective view of the front side seen obliquely from above, and FIG. 9is a perspective view of the back side seen obliquely from above inwhich an upper half of a duct is removed. FIG. 10 is a perspective viewin which a holder of the light source lamp in FIG. 9 is removed, andFIG. 11 is a cross-sectional view of the principal parts seen from theback side.

The light source lamp 19 of the present embodiment has an arc tube 191composed of a high-pressure mercury lamp, the metal-halide lamp, and thelike, and a reflector 192 disposed so as to cover this arc tube 19 andformed in the inner surface with a paraboloidal reflecting surface andopened in the front surface. This reflector 192, as shown in FIG. 10, isformed with a suction port 193 and an exhaust port 194 opposed to eachother on the front surface opening edge.

The light source lamp 19 thus configured is loaded on a lamp holder 195made of aluminum as shown in FIGS. 8 and 9. This aluminum lamp holder195 is configured to be provided with a heat-resisting glass plate 196blocking a front surface opening of the reflector 192, and at the sametime, formed with a ventilation wire netting 197 composed of a largenumber of small holes corresponding to the suction port 193 and theexhaust port 194 of the reflector 192, so that the fragment does not flyin all directions when the arc tube 191 is burst.

The conventional light source lamp cooling mechanism is disposed withthe fan and the discharge portion in consideration of the cooling onlyof the light source lamp, and therefore, even when the cooling of thelight source lamp is performed, by that much, the exhaust temperatureincreases. The projection type image display apparatus such as theliquid crystal projector has come to require a raised output of thelight source lamp and the miniaturization of the apparatus all together,and in the conventional art as explained above, even if the cooling ofthe light source lamp of a high output can be performed, the exhausttemperature exceeds a permissible zone of the user and increases toomuch, thereby making it difficult to achieve both the cooling of thelight source lamp and a reduction in the exhaust temperature. As itscountermeasure, when the output (the number of rotations) of the fan isincreased, the noise of the fan is increased.

Hence, the present embodiment includes, as a fan to cool the lightsource lamp 19, the suction fan (first fan) 16 having the innerdischarge port 161 sending the air through the suction port 193 formedin the reflector 192 inside the light source lamp 19 and the outerdischarge ports 162 and 163 sending the air to the outer surfaces of thereflector 192, and the exhaust fan (second fan) 17 exhausting an exhaustair around the light source lamp 19 to the outside through an exhausthole 8 formed in the side wall of the housing 2. The suction fan 16 iscomposed of the sirocco fan, and the exhaust fan 17 is composed of theaxial fan.

The outer discharge ports 162 and 163 of the suction fan 16 are formedby deviating from the outer surface center portion of the reflector 192of the light source lamp 19, and at the same time, the exhaust fan 17 isdisposed inclined such that its suction direction is directed toward theouter discharge ports 162 and 163 of the suction fan 16.

Each of the discharge ports 161, 162, and 163 circularly bends thedistal end of the duct 164 to the light source lamp 19 side and isformed on its distal end, the duct 164 extending to the lateral side ofthe light source lamp 19 from the suction fan 16 disposed at the lateralside in the irradiation direction of the light source lamp 19. An innerdischarge port 161 is formed by corresponding to a suction port 193formed in the reflector 192 of the light source lam 19, while the outerdischarge ports 162 and 163 are formed above and below two pieces bydeviating vertically from the outside surface center portion of thereflector 192 of the light source lamp 19.

As explained above, the degree of deviating the outer discharge ports162 and 163 of the suction fan 16 from the outside surface centerportion and the degree of inclining the exhaust fan 17 such that itssuction direction is directed to the outer discharge ports 162 and 163of the suction fan 19 are set in consideration of the cooling of thelight source lamp 19 and the exhaust temperature.

By being thus configured, the interior of the light source lamp 19having the arc tube 191 reaching the highest temperature can beeffectively cooled by using the inner discharge port 161 of the suctionfan 16. The outer surface (including a neck portion 198 projected fromits back end) of the reflector 192 of the light source lamp 19, whichdoes not reach the temperature high enough as the interior of the lightsource lamp 19, can be suitably cooled by using the outer dischargeports 162 and 163 of the suction fan 16 formed by deviating from theouter surface center portion.

Since the exhaust fan 17 is disposed inclined such that its suctiondirection is directed to the outer discharge ports 162 and 163 of thesuction fan 16, the air from the outer discharge ports 162 and 163 ofthe suction fan 16 formed by deviating from the outer surface centerportion of the light source lamp 19 cools the outer surface of the lightsource lamp 19, and at the same time, a part of the air is directlysucked into the exhaust fan 17, and is mixed with the exhaust airincreased in temperature by having cooled the interior of the lightsource lamp 19, and is exhausted to the outside, thereby reducing theexhaust temperature.

Consequently, without increasing the outputs of the suction fan 16 andthe exhaust fan 17 so much, the cooling of the light source lamp 19 andthe reduction in the exhaust temperature can be both achieved, so thatthe noise can be also suppressed low.

Further, by forming the outer discharge ports 162 and 163 of the suctionfan 16 above and below two pieces by deviating from the outer surfacecenter portion of the light source lamp 19, the outer surface of thelight source lamp 19 can be approximately equally cooled.

The degree of deviating each of the discharge ports 161 and 162 of thesuction fan 16 from the outer surface center portion of the light sourcelamp 19 and the degree of inclining the exhaust fan 17 such that itssuction direction is directed toward the outer discharge ports 162 and163 of the suction fan 16 are set in consideration of the cooling of thelight source lamp 19 and the exhaust temperature, and therefore, thecooling of the light source lamp 19 and the reduction in exhausttemperature can be both flexibly achieved in conformity with the raisedoutput of the light source lamp 19, the miniaturization of theapparatus, and the like.

Further, each of the discharge ports 161, 162, and 163 of the suctionfan 16 is formed in the duct 164 extended from the suction fan 16 to thelight source lamp 19, so that a degree of freedom of the positioning ofthe suction fan 16 is improved.

Thus, according to the present embodiment, since the light source lampcooling mechanism as explained above is provided, so that, withoutincreasing the outputs of the fans 16 and 17 so much, the liquid crystalprojector 1 capable of achieving the cooling of the light source lamp 19and the reduction of the exhaust temperature as well as reducing thenoise can be realized.

FIGS. 12 to 15 are enlarged views of the principal parts showing anoptical part cooling mechanism in the present embodiment. FIG. 12 is aperspective view seen obliquely from above from the front side, FIG. 13is a top plan view, FIG. 14 is a top plan view in which optical partssuch as the liquid crystal panels and the like are removed, and FIG. 15is a back view in which the lower half of the duct is removed.

As explained earlier, heretofore, there has been known a device coolingthree pieces of liquid crystal panels corresponding to a red light, agreen light, and a blue light and polarizing plates disposed at theincident side and the outgoing side of each liquid crystal panel by oneset of the fan every color, that is, by a total of three sets of thefans.

Meantime, three pieces of the liquid crystal panels corresponding to thered light, the green light, and the blue light, and the polarizingplates and the like disposed at the incident side and the outgoing sideof each liquid crystal panel are different in temperature rise anddegree of ultraviolet deterioration every color, and therefore, therequired cooling amount is also different. Particularly, since the bluelight is close to the ultraviolet region, to avoid the ultravioletdeterioration, the required amount of cooling becomes large.

The projection type image display apparatus such as a liquid crystalprojector and the like has come to require the enhancement of luminanceby the raised output of the light source lamp, the miniaturization ofthe apparatus, and a reduced cost (miniaturization of the liquid crystalpanel and the like) all together, and the amount of light per unit areaof high luminance has come to be increased.

However, the conventional art that performs cooling by one set of thefan for each color has been unable to cope with the model whose amountof light per unit of high luminance has come to be increased. As acountermeasure, when the output of the fan (the number of rotations) isincreased, the noise of the fan is increased. Further, the cooling ofthe PBS needs to be also performed.

Hence, in the present embodiment, the incident side and the outgoingside of each of the liquid crystal panels 34 r, 34 g, and 34 b areformed with discharge ports r1 and r2, g1 and g2, and b1 and b2 todischarge the air from three sets of suction fans 41, 42, and 43 throughducts 411, 421, and 431. At the same time, the PBS 23 is formed with adischarge port p1 to discharge the air from the suction fan 43 throughthe duct 432. An incident side discharge port b1 and an outgoing sidedischarge port p2 of the liquid crystal panel 34 b corresponding to theblue color are formed with a duct so as to discharge the air from thesuction fans 43 and 41 which are different from each other.Incidentally, each of the suction fans 41 to 43 is composed of thesirocco fan.

That is, the duct is configured such that, by one set of the suction fan43, the air is sent to the incident side discharge port b1 of the liquidcrystal panel 34 b corresponding to the blue light and the dischargeport p1 of the PBS 23, and by the other two sets of the suction fans 41and 42, the air is sent to the incident side discharge ports r1 and g1of each of the liquid crystal panels 34 r and 34 g, to the outgoing sidedischarge port r2 and g2 corresponding to the red light and the greenlight, and to the outgoing side discharge port b2 of the liquid crystalpanel 34 b corresponding to the blue light.

To explain more specifically, the duct is configured such that, by oneset of the suction fan 42 from among two sets of the suction fans 41 and42, the air is sent to the incident side discharge port g1 and to theoutgoing side discharge port g2 of the liquid crystal panel 34 gcorresponding to the green light through the duct 421, and by the otherset of the suction fan 41, the air is sent to the incident sidedischarge port r1 and to the outgoing side discharge port r2 of theliquid crystal panel 34 r corresponding to the red light and theoutgoing side discharge port b2 of the liquid crystal panel 34 bcorresponding to the blue light by extending the duct 411.

By being thus configured, by three sets of the suction fans 41 to 43,the incident side and the outgoing side of each of the liquid crystalpanels 34 r, 34 g, and 34 b in addition to the PBS 23 can be cooled. Theincident side and the outgoing side of the blue light which is large inrequired cooling amount can be sufficiently cooled by using the suctionfans 43 and 41 which are different from each other. Consequently, evenwhen the amount of light per unit area of high luminance is increased,without increasing the output (the number of rotations) of the suctionfans 41 to 43 so much, the liquid crystal panels 34 r, 34 g, and 34 b,and the polarizing plates 36 r, 36 g, 36 b, 37 g, 37 b, 38 r, 38 g, and38 b, and the PBS 23 can be cooled by three sets of the suction fans 41to 43, thereby reducing the noise also.

Further, the duct is configured such that, by one set of the suction fan43, the air is sent to the incident side discharge portion b1 of theliquid crystal panel 34 b corresponding to the blue light and to thedischarge port p1 of the PBS 23, and by the other two sets of thesuction fans 41 and 42, the air is sent to the incident side dischargeports r1 and g1, to the outgoing side discharge ports r2 and g2 of eachof the liquid crystal panels 34 r and 34 g corresponding to the redlight and green light, and to the outgoing side discharge port b2 of theliquid crystal panel 34 b corresponding to the blue light, so that, inthe system disposed with the liquid crystal panel 34 b of the blue lightat the PBS 23 side similarly to the optical system 13 of the presentembodiment, by the shortest duct configuration, the above explainedeffect can be realized. Further, by the suction fan 41 for red lightthat increases least in temperature, the air can be sent to the outgoingside discharge port b2 of the liquid crystal panel 34 b corresponding tothe blue light. Incidentally, if the suction fan for the green lightthat increases most in temperature is not enough with one set of thesuction fan 42, the air may be sent from the suction fan 41 for redlight.

Similarly to the present embodiment, the duct is configured such that,by one set of the suction fan 42 from among the two sets of suction fans41 and 42, the air is sent to the incident side discharge port g1 and tothe outgoing side discharge port g2 of the liquid crystal panel 34 gcorresponding to the green light, and by another one set of the suctionfan 41, the air is sent to the incident side discharge port r1, to theoutgoing side discharge port r2 of the liquid crystal panel 34 rcorresponding to the red light, and to the outgoing side discharge portb2 of the liquid crystal panel 34 b corresponding to the blue light, sothat the above explained effect can be realized without the ductconfiguration becoming complicated.

Thus, according to the present embodiment, since the apparatus isprovided with the optical part cooling mechanism as explained above,even when the amount of light per unit area of high luminance isincreased, without increasing the output (the number of rotations) ofthe fan so much, the liquid crystal panel and the polarizing plate aswell as the PBS can be cooled by three sets of the fans, so that theliquid crystal projector 1 capable of reducing the noise can berealized.

Next, the power source unit of the present embodiment will be explained.

Heretofore, it has been common to mount a noise removal filter portionon the circuit substrate of the power source unit.

As explained above, the projection type image display apparatus such asa liquid crystal projector and the like has come to require theenhancement of luminance by the raised output of the light source lamp,the miniaturization of the apparatus, and a reduced cost all together,and because of the raised output of the light source lamp, the powersource unit has also come to require a large output.

However, in the case of the model having a small output, even when thenoise removal filter is mounted on the circuit substrate of the powersource unit similarly to the conventional art, this does not cause aproblem. However, when the output becomes large, a noise removal filterportion having a core (coil) incapable of being miniaturized becomeslarge, thereby upsizing the power source unit.

When the power source unit becomes large, the fan that cools this powersource unit also becomes large, and the output (the number of rotations)is required to be increased. This results in lowering of the coolingperformance and making the noise large. As its countermeasure, though itis conceivable to separate the noise removal filter portion and make itinto a separate type, a noise is liable to enter the connecting line,and because of the increased use of the core, the EMC (ElectroMagneticCompatibility) measure becomes formidable thereby inviting a high cost.

Hence, in the present embodiment, as explained above, the noise removalfilter portion 15 is separated from the power source unit main body 14,and at the same time, the separated noise removal filter portion 15 isdisposed to be positioned as closely as possible to the housing backside wall provided with the power source inlet 10 and the power unitmain body 14, respectively.

Specifically, along the front side wall of the horizontally long house2, the power source unit main body 14 is disposed, and at the positionopposed to the power source unit main body 14 in the back side wall, thenoise removal filter portion 15 is disposed along the back side wall.

By being thus configured, even when the output of the light source lamp19 becomes large, the power source unit main body 14 can beminiaturized, so that a reduction in the noise can be made possible bythe improvement of the cooling performance. In addition, the connectingline is minimized, so that a reduction in the cost is made possible bymaking the EMC measure (reduction in the use of the core and the like)more effective.

Further, by disposing the noise removal filter portion 15 close to thehousing back side wall provided with the power source inlet 10, a powersource cord is not brought to the lateral side of the housing 2, so thatthe above explained effect can be obtained with the usability of thelateral side of the housing 2 not harmed.

Further, the power source unit main body 14 is disposed along the frontside wall of the horizontally long house 2, and by disposing the noiseremoval filter portion 15 at the position opposed to the power sourceunit main body 14 in the back side wall, even when the noise removalfilter portion 15 is disposed along the back side wall, the connectingline can be made shortest, so that the above explained effect can beobtained without making the disposal configuration of each part insidethe housing 2 complicated.

Thus, according to the present embodiment, the power source unit asexplained above is provided, so that even when the output of the lightsource lamp 19 becomes large, the liquid crystal projector 1 capable ofreducing the cost by a reduction of the noise by improving the coolingperformance and making the EMC measure more effective can be realized.

Incidentally, in the present embodiment, since the housing 2 ishorizontally long, even when the power source unit main body 14 and thenoise removal filter portion 15 are arranged in parallel along the frontside wall and the back side wall, respectively, the connecting line canbe made shortest, while in the case of the housing vertically long frontto back, the disposition as explained above is unable to make theconnecting line shortest, and therefore, in this case, for example, ifthe noise removal filter is disposed front and back, then, it ispossible to dispose the noise removal filter portion close to thehousing back side wall and the power source unit main body,respectively.

Next, the exhaust mechanism in the present embodiment will be explained.

Heretofore, there has been known the exhaust mechanism placed with twosets of exhaust fans side by side close to the light source lamp, theexhaust fans exhausting the exhaust air to the outside from the lightsource lamp, the power source unit, and the like.

As explained above, while the projection type image display apparatussuch as the liquid crystal projector has come to require the raisedoutput of the light source lamp and the miniaturization of the apparatusall together. The exhaust air of high temperature from the high outputlight source lamp is exhausted, but a reduction in the exhausttemperature and a reduction in the noise of the exhaust fan have becomea key issue.

However, to achieve a reduction in noise of the side by side exhaustfans installed by the conventional art as explained above, a space needsto be left between the fan and the housing side wall, and this hindersthe miniaturization. To reduce the temperature of the exhaust air, it isconceivable to dispose each of the exhaust fans installed side by sideso as to be inclined in a V shape in the mutual exhausting direction sothat the exhaust air of high temperature from the light source lamp andthe exhaust air of the relatively low temperature from the power sourceunit and the like are mixed, but even in this case also, a spacetherefore is required, and the miniaturization is thus hindered.

Hence, in the present embodiment, as shown in FIGS. 3, 4, and the like,the first exhaust fan 17 which mainly exhausts the exhaust air from thelight source lamp 19 (light source lamp unit 12) to the outside and thesecond exhaust fan 18 which mainly exhausts the exhaust air from thepower source unit main body 14 to the outside are horizontally installedside by side, and at the same time, the second exhaust fan 18 side endportion in the first exhaust fan 17 is moved inward, and the firstexhaust fan 17 is disposed inclined such that its exhaust direction isdirected to the exhaust side of the second exhaust fan 18.

The first exhaust fan 17 is disposed inclined to a large number ofslit-like exhaust holes 8 formed in the housing side wall, and moreover,is disposed inclined such that the exhaust air from the exhaust holes 8are exhausted inclined obliquely forward.

The first exhaust fan 17 and the second exhaust fan 18, as shown inFIGS. 16 and 17, are fixed to a frame body 50 in advance and unitized soas to take on the above explained disposal configuration, and when thisexhaust fan unit 51 is fitted to the predetermined position of the lowercase 2 b of the housing 2, the above explained disposal configurationcan be easily realized. Incidentally, since the first exhaust fan 17sucks down the exhaust air of high temperature from the light sourcelamp 19, as shown in FIG. 17, the back side is configured to be coveredby a cover 52 with the center motor portion blocked and protect themotor portion from the exhaust air of high temperature from the lightsource lamp 19.

By being thus configured, the first exhaust fan 17 is inclined inward,so that the miniaturization is not hindered, and further, a space can beformed between the housing side wall and the first exhaust fan 17,thereby reducing the noise to a lower level. Further, the exhaust air ofhigh temperature from the light source lamp 19 and the exhaust air ofthe relative low temperature from the power source unit main body 14 aremixed, thereby reducing the temperature of the exhaust air.

Since the light source lamp is brought to a high temperature, and isdisposed spaced further apart from the exhaust fan than before, theabove explained configuration and effect can be easily realized.

Further, since the second exhaust fan 18 exhausts the exhaust air mainlyfrom the power source unit main body 14 to the outside, it can alsosimultaneously exhaust the exhaust air of the important power sourceunit main body 14, though not higher in temperature than the lightsource lamp 19.

Further, the first exhaust fan 17 which exhausts the exhaust air fromthe light source lamp 19 to the outside is disposed inclined to a largenumber of slit-like exhaust holes 8 formed in the housing side wall, sothat the air in high temperature from the light source lamp 19 isexhausted obliquely from a large number of slit-like exhaust holes 8,and by that much, the exhaust air becomes hard to be exhausted, therebyto be easily mixed with the exhaust air of the relatively lowtemperature from the second exhaust fan 18 with a result that theexhaust air temperature can be reduced much more than before.

Further, the first exhaust fan 17 which exhausts the exhaust air fromthe light source lamp 19 is disposed inclined so as to exhaust obliquelyfrontward the exhaust air from the exhaust holes 8 formed in the housingside wall, so that the exhaust air of high temperature can be preventedfrom being laterally blown out to an operator and the like.

Thus, according to the present embodiment, since the exhaust mechanismas explained above is provided, the liquid crystal projector 1 capableof reducing the noises of the exhaust fans 17 and 18 and lowing theexhaust temperature, while achieving down-sizing can be realized.

Incidentally, in the present embodiment, though the first exhaust fan 17has been inclined, if an extra room available inside space-wise, evenwhen the second exhaust fan 18 is conversely inclined similarly to thefirst exhaust fan, a fixed effect can be expected.

1. A projection type image display apparatus for modulating lightemitted from a light source lamp based on an image signal to project themodulated image light in an expanded manner, comprising: a first exhaustfan for mainly discharging exhaust air from the light source lamp toexterior; and a second exhaust fan for mainly discharging exhaust airfrom parts other than the light source lamp, wherein the first exhaustfan and the second exhaust fan are arranged to be parallel to eachother, and the first and second fans are arranged so that an end of oneexhaust fan facing the other exhaust fan is moved to the inner side, andthat the one exhaust fan is inclined to discharge air in an exhaustdirection toward a direction along which air is discharged from theother exhaust fan.
 2. The projection type image display apparatusaccording to claim 1, wherein an end of the first exhaust fan facing thesecond exhaust fan is moved to the inner side, and the first exhaust fanis inclined so that air is discharged from the first exhaust fan in adirection to the exhaust of the second exhaust fan.
 3. The projectiontype image display apparatus according to claim 1, wherein the secondexhaust fan mainly discharges exhaust air from a power source unit toexterior.
 4. The projection type image display apparatus according toclaim 1, wherein the first exhaust fan is inclined to an exhaust holeformed in a side wall of a housing.
 5. The projection type image displayapparatus according to claim 1, wherein the first exhaust fan isinclined so that exhaust air is discharged through an exhaust holeformed in a side wall of a housing to the front side in an inclineddirection.
 6. The projection type image display apparatus according toclaim 1, wherein the projection type image display apparatus includes acooling fan that blows air to an interior air blow outlet communicatingwith the interior of the light source lamp and an exterior air blowoutlet communicating with an outer surface to cool the light sourcelamp, the exterior air blow outlet is deviated from the center of theouter surface of the light source lamp, the cooling fan is used to allowthe exhaust air used for cooling the light source lamp to be dischargedthrough the first exhaust fan, and the first exhaust fan is inclined sothat air is sucked by the first exhaust fan in a direction to theexterior air blow outlet.
 7. The projection type image display apparatusaccording to claim 2, wherein the second exhaust fan mainly dischargesexhaust air from a power source unit to exterior.
 8. The projection typeimage display apparatus according to claim 3, wherein the first exhaustfan is inclined to an exhaust hole formed in a side wall of a housing.9. The projection type image display apparatus according to claim 4,wherein the first exhaust fan is inclined so that exhaust air isdischarged through an exhaust hole formed in a side wall of a housing tothe front side in an inclined direction.
 10. The projection type imagedisplay apparatus according to claim 6, wherein the exterior air blowoutlet is deviated from the center of the outer surface of the lightsource lamp and is divided to two of upper and lower parts.
 11. Theprojection type image display apparatus according to claim 6, wherein adegree at which the exterior air blow outlet is deviated from the centerof the outer surface of the light source lamp, and a degree at which thesecond fan is inclined so that air is sucked by the second fan in adirection to the exterior air blow outlet, are determined inconsideration of the cooling of the light source lamp and the exhaustair temperature.
 12. The projection type image display apparatusaccording to claim 6, wherein the interior air blow outlet and theexterior air blow outlet are formed in a duct extending from the firstfan to the light source lamp.
 13. The projection type image displayapparatus according to claim 7, wherein the first exhaust fan isinclined to an exhaust hole formed in a side wall of a housing.
 14. Theprojection type image display apparatus according to claim 8, whereinthe first exhaust fan is inclined so that exhaust air is dischargedthrough an exhaust hole formed in a side wall of a housing to the frontside in an inclined direction.
 15. The projection type image displayapparatus according to claim 10, wherein a degree at which the exteriorair blow outlet is deviated from the center of the outer surface of thelight source lamp, and a degree at which the second fan is inclined sothat air is sucked by the second fan in a direction to the exterior airblow outlet, are determined in consideration of the cooling of the lightsource lamp and the exhaust air temperature.
 16. The projection typeimage display apparatus according to claim 11, wherein the interior airblow outlet and the exterior air blow outlet are formed in a ductextending from the first fan to the light source lamp.
 17. Theprojection type image display apparatus according to claim 13, whereinthe first exhaust fan is inclined so that exhaust air is dischargedthrough an exhaust hole formed in a side wall of a housing to the frontside in an inclined direction.
 18. The projection type image displayapparatus according to claim 15, wherein the interior air blow outletand the exterior air blow outlet are formed as a duct extending from thefirst fan to the light source lamp.